Air foil



Aug. 23, 1932. c R|CKARD 1,873,664

AIR FOIL Filed May 13, 1931 5 Sheets-Sheet l C. E. Hi chard Aug. 23, 1932. c. E. RICKARDV AIR FOIL a Sheets -Sheet 2 Filed May 13, 1951 5'. E. E152; 3rd

Aug. 23, 1932. c. E. RICKARD AIR FOIL Filed May 13. 1931 3 Sheets-Sheet 3 Patented Aug. 23, 1932 CHET E. BICKABD, OI ANACONDA, MONTANA an. Iron.

Application filed Kay 18, 1981. Serial No. 587,085.

This invention relates to air foils of that general type comprising a pair of blades or lanes which preferably are rigid and camered in construction and attached to the sup- 6 porting member at or near the center of rotation and are adapted to be revolved, as in a helicopter, or self-rotated, as in an'autogiro.

An object of the present invention is to provide a blade of this character in which a V- shaped opening is provided in the trailing edge of the blade from the tip to the inner end of the blade to produce a partial vacuum which has been found, in practice, to increase the lifting and sustaining function of the blade.

A still further object is to provide a novel hub having sockets which receive the shafts of opposite blades and positively prevent any tendency of the blades to rotate on their axes, while, at the same time, permitting of a pivotal adjustment of the shafts to vary the angle of incidence of the blades.

A still further object is to provide a shaft for the blade comprising a grid truss to which the ribs may be firmly secured to provide a more rigid construction of blade than hitherto ossible.

K still further object is to provide novel ribs over which the fabric or other covering of the blade may be stretched, the ribs being of substantially V-shaped contour and provided with seats upon which the lower longi tudinal member of the shaft may be rigidly bolted, and provided above the seats with bearing surfaces to which the upper longitudinal member of the shaft may be rigidly bolted to further promote rigidity in the blade structure.

With the above and other objects in view the invention consists in certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be resorted to within the scope of the appended claims Without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawings forming part of this specification,

Figure 1 is a side elevation of an autogiro equipped with my improved blades or sustaming wings,

Fig. 2 is a plan view of the autogiro,

Flg. 3 is a bottom plan view of one of the blades, with a portion broken away toexpose the ribs and shaft,

Fig. 4 is a rear elevation of the blade shown 1n Fig. 3,

Fig; 5 is an enlarged cross sectional view taken on the line 5-5 of Fig. 3, v

Fig. 6 is a detail perspective view of one of the ribs, and h gig. 7 is a detail perspective view of the Referring now to the drawings in which like characters of reference designate similar parts in the various -views, 10 designates an aircraft of the autogiro type, having the usual upright support -11 to which the rotatmg sustaining air foils are secured. However, the invention is not limited to autogiros as 1t may be equally well applied to helicopters or other aircrafts.

In carrying out the invention, I provide a blade comprising essentially a plurality of substantially V-shaped ribs 12, best shown in Fig. 6, each rib being formed of metal shaped to provide an upper cambered member 13, a lower straight member 14, and a substantially V-shaped intermediate member 15 the legs of which are integral with the trailing ends of the upper and lower members, and the apex 16 of which is turned toward the juncture 17 of the upper and lower members, which juncture forms the leading edge of the rib. Diagonally disposed braces 18 and 19 connect the upper and lower members respectively with the V-shaped intermediate member and brace the rib against distortion. The intermediate member is provided in the lower leg thereof with a substantially right angular seat 20 to receive the hereinafter described shaft of the blade.

The ribs, constructed as above described, are preferably formed in various sizes to produce a tapered contour of the blade, as shown best in Fig. 2, the blade tapering from a point 21 adjacent to the inner end toward the tip 22 of the blade, and also tapering per leg of each rib. The cloth covering 31 abruptly from said point toward the inner end 23 of thegbladei blade where the churning effect is usually eatest.

. gr To complete the construction of the blade,\. In further carrying out the invention, I

I provide a shaft 24, best shown in Figs. 3, 4, and 5, and comprising a grill or truss including upper and lower longitudinal rails 25 connected at intervals by cross braces 26 and stayed by wires or diagonal metal rods 27. The rails 25 are rectangular in cross section, and, preferably, these rails as well as the braces 26 may be formed of aluminum or other light strong metal. The inner ends of the longitudinal rails 25 are brought close together and connected integrally with a substantially rectangular hollowferrule 28. A

plurality of openings 29 are formed in the sides of the ferrule to secure the shaft to the hereinafter described hub.

In assembling the shaft with the ribs, the bottpm rail of the shaft is seated on the above described angular seat 20 of the intermediate member 15 of all of the ribs, while the uppermost rail is butted against the lower surface of the upper leg of said intermediate memher, as best shown in Fig. 5. Both rails are then securely bolted, as shown at 30, or otherwise rigidly secured to the seat and to the upor other covering may then be secured to the ribs in any preferred manner, to complete the blade assembly. If desired, a box 32 may be secured in the usual manner to connect all of the ribs within the enclosure formed by the upper and lower members of the ribs at the leading ends thereof in order to further reinforce and stiffen the blade structure.

It will be observed, by referring to Figs. 1 and 5, that the blade structure thus produced exhibits a substantially V-shaped indentationat the trailing edge. In practice it has been found that the partial vacuum created in this indentation by rotation of the blade assists in materially enhancing the lifting or sustaining power of the blade.

It will be further pointed out that in constructing the ribs 12, the ribs nearest the in ner orbutt end of the blade, as best disclosed in Fig. 3, have upper members 13 of greater length than those located near the tip of the blade, while the lower members 14 of all of the ribs are equal in length. As a result of this'construction, the trailing edge 33 of the lower surface of the blade will be substantiaL 1y parallel with the upper lower rails of the connecting shaft, while the trailing edge 34 of the upper surface of the blade will overhang the trailing edge of the lower surface to a gradually increasing extent as the trail ing edge progresses from the tip of the wing to a point near the hub. As a result of this overhanging construction, in practice it has been found that the effectiveness of the blade is greatly increased due to the upper surface of the blade overhanging the lower surface to a considerable extent at the inner end of the prBvide a hub, best shown in Fi 7 and comprising a substantially rectan ar socket 35 adapted to be fitted upon the above mentioned uprlght support 11 which is of similar cross section, as will be understood. A nut 36 and cotter pin 37, best shown in Fi 1, firmly secure the socket against a shou der 38 on the support. By again referring to Fig. 7, it will be seen that a plurality of radial sleeves 39 are preferably cast integral with thesocket and are of substantially rectangular cross section to receive the ferrules 28 of the shafts of the blades.

Each sleeve 39 is provided with a plurality of vertically disposed slots 40 to receive bolts 41, best shown in 4, for rigidly securing the ferrule of the corresponding blade in the sleeve. The slots permit of pivotal adjustment of the blades, as will be understood, to change the angle of incidence of the blade While my improved blades have been shown as applied to an autogiro, it is to be understood that, if desired, in lieuof the support 11 a power-driven shaft may be operatively connected to the motor to positively drive the wings instead of permitting of the wings to auto-rotate, as in the usual autogiro type of aircraft.

By referring to Fig. 3, it.will be seen that a pair of strips 42 are secured to the ribs at the leading and trailing edges to tie the ribs together and equalize the strain on the main shaft of the blade.

Having thus described the invention, I claim:

1-. An air foil comprising ribs of V-shaped cross section, a covering for the ribs, said ribs providing a V-shaped recess longitudinally of the trailing edge of the air foil, and a shaft connecting the ribs longitudinally throughout the air foil and disposed within said recess.

2. An air foil comprising skelton ribs shaped to provide upper and lower members diverging from the leading edge to the trailing edge of the air foil, intermediate substantially V-shaped members connecting the upper and lower members and having the apices turned towards said leading edge, a covering disposed on said upper, lower and intermediate members, and a longitudinal skeleton shaft rigidly connecting the ribs together throughout the length of the air foil.

3. An air foil comprising ribs of substantially V-shaped cross section providing a longitudinal recess throughout the length of the air foil at the trailing edge thereof, and a shaft connecting said ribs and disposed within said recess and comprising upper and lower rails connected by vertical braces, the ribs disposed near the inner end of the air foil being of eater length than the ribs disposed near t e ti of the air foil whereby the upper surface 0 the air foils overhangs and projects rearwardly beyond the lower surface of the air foil near said inner end of the air foil.

4. An air foil comprising metal ribs of V-shaped contour comprising upper and lower divergin members connected at the trailing edges by a V-shaped intermediate member with the apex turned toward the leading ends of the upper and lower members, braces rigidly connecting the upper and lower members with the V-shaped intermediate member, a seat formed on the lower leg of the intermediate member, a longitudinal shaft connecting all of said ribs and seated on the seat of each rib, and a cover for the ribs.

5. An air foil comprising substantially V-shaped ribs providing a longitudinal recess throughout the trailing edge of the air foil, a cover for theribs, a longitudinal shaft connecting all of the ribs and disposed within said recess and terminating in a ferrule, a hub having a socket receiving said ferrule, and means pivotally securing said ferrule in the hub to permit of changing the angle of incidence of the air foil.

In testimony whereof I-afi'ix my si nature.

CHET E. RICKARD. a. a] 

